Dear SCO Customer,

The enclosed Support Level Supplement (SLS) PTF3123B, the Networking 
Maintenance Supplement, supersedes the previous version, PTF3123. Issues
were found with installing and removing the original SLS PTF3123; if certain
network related packages were not installed on the target system, it would
fail to install, and, in removing PTF3123, the libsocket library links were
not restored.

SLS PTF3123B corrects the following problems:

1. Routines in libsocket fail to reset the file descriptor type after closing
   a file/device. As a result, upon reallocation of the same file descriptor 
   failures may occur on functions with file type-specific behavior. For 
   instance, functions that read or write sockets may fail if the file 
   descriptor in use was previously allocated for a regular or other non-socket 
   type file.

2. A DOS emulation cannot be executed on a remote system. After starting an
   interactive shell on a remote system using xterm(1), executing the dos(1)
   command to run the DOS emulation on the remote system will fail and may 
   produce a core dump.

3. An ftpd(1m) transfer may abort and produce an error indicating that a 
   socket operation was attempted on a non-socket device. This problem is one 
   manifestation of problem number 1. This specific problem has been found and 
   reported multiple times and this separate problem description is included 
   to emphasize that this supplement addresses the ftpd problem.

4. During a failover to the redundant system, NFS clients using NFS mounted
   filesystems may fail with the error message:

        NFS 151 Error

   The failing process will not continue and data corruption may result.

5. For files on NFS mounted filesystems, the chown(1) and chgrp(1) commands
   will fail. When executed as the "root" user, chown makes "root" the file
   owner no matter what "owner" is specified on the command line.  The chgrp 
   command will not change the file group value no matter which user executes 
   the command.

6. A TCP/IP client program, failing to reconnect on an endpoint on which a 
   disconnect request has been sent, continuously produces messages from
   the server system instead of failing with a T_DISCONNECT status.

7. An Internet application may fail with the following message:

        accept: Protocol error

   Server processes requesting many disconnects may produce this error.

8. Socket device driver code (sockmod) allows memory leakage.

9. TCP device driver code (tcp) allows division by zero which may lead to a
   system PANIC.


Software Notes and Recommendations
----------------------------------

In addition to the problem fixes described above, PTF3123B includes a libsocket
fix that is also in PTF3107, the Single UNIX Specification Supplement. That
fix corrects problems with a libsocket library utility which caused an infinite 
loop when a zero-length buffer was passed into the routine.

To prevent the overlay of the PTF3123B libsocket library by that from the
earlier PTF, which would result in the regression of libsocket with the loss
of the fixes described in the section above, PTF3123B requires that PTF3107 
remains installed.

PTF3123B should only be installed on SCO UnixWare Application Server Release
2.1.1 or SCO UnixWare Personal Edition Release 2.1.1


Installation Instructions
-------------------------
1. Become root and create a new directory by typing the following:
 
     $ su
     Password: <type your root password>
     # mkdir /tmp/pkg
     # chmod 700 /tmp/pkg
     # cd /tmp/pkg

2. Download the ptf3123b.Z and the ptf3123b.txt files to the newly
   created /tmp/pkg directory on your machine.
 
3. Read the Release Notes contained in the ptf3123b.txt file.
 
4. Uncompress the file and add the package to your system using these
   commands:
 
     # uncompress /tmp/pkg/ptf3123b.Z
     # pkgadd -d /tmp/pkg/ptf3123b 


Removal Instructions
---------------------

1. Become root and remove the package by typing these commands:

    $ su
    Password: <type your root password>
    # pkgrm ptf3123


If you have questions regarding this SLS, or the product on which it is
installed, please contact your software supplier.

We appreciate your business.

SCO Support Services